Osteoarthritis of the knee, also called gonarthrosis, is a disease that is booming in Western countries. According to Inserm, 10 million French people are affected (65% of those over 65).
Osteoarthritis is the wear and tear of the cartilage, that is, the tissue that covers the bone at the joints to allow movement. Osteoarthritis of the knee causes pain and loss of mobility of the knee. ‘joint. Those affected often find it difficult to move”, summarizes Dr. Arnaud Clavé, orthopedic surgeon at the Saint George clinic in Nice.
Osteoarthritis of mechanical origin and related to aging (aggravated or not by trauma) are today the most frequent. “Because the joint ages, a bit like the tires of a car. The wear depends on the anatomy and the quality of cartilage of each person”, he continues.
To date, the only curative treatment remains the placement of a knee prosthesis. “The use of this intervention has exploded over the past ten years due to the legitimate desire of patients to maintain an optimal quality of life, but also thanks to the improvement of surgical techniques and implants. There are two solutions: the total prosthesis or the partial or unicompartmental prosthesis (PUC).
Little used and less known, this second alternative is nevertheless minimally invasive. Dr. Arnaud Clavé has studied this method in detail. In 2020, with Dr Frédéric Dubrana, orthopedic surgeon and traumatologist in Brest, the surgeon from Nice published the book, unicompartmental knee prosthesis. He explains how PUC works and its advantages. We take stock.
Why a partial knee prosthesis?
For biomechanical reasons, the internal femoro-tibial compartment is the most subject to knee wear and affects more than 60% of patients with symptomatic osteoarthritis.
“Because it is in this compartment that the weight of the body passes when walking. Thus in many cases of osteoarthritis of the knee, it is not necessary to replace the entire joint and therefore to have recourse to a total prosthesis.
“The unicompartmental prosthesis is an interesting alternative. It replaces – only – the internal femoro-tibial compartment that has been destroyed.”
What is the principle?
“The principle of a half-prosthesis is to act as a small wedge that will compensate for the wear of the damaged compartment without affecting the capsule-ligament envelope.”
It recreates the state and biomechanical functioning of the knee.
Who is she talking to?
To benefit from the unicompartmental partial prosthesis, you must have advanced osteoarthritis of the internal femoro-tibial compartment, a functional cruciate ligament, a patella that is not too damaged and a healthy knee envelope.
How is the operation carried out?
The intervention takes place under multimodal anesthesia (general anesthesia, loco-regional anesthesia and local anesthesia) or under spinal anesthesia and lasts from 30 to 60 minutes.
“The patient is lifted and encouraged to walk in the hours following their surgery. This operation can therefore be performed on an outpatient basis if the patient adheres to this treatment plan.
The discharge can be done at home and it is only exceptionally necessary to have recourse to a rehabilitation center, the latter can be done at a physiotherapist in town.
What is the difference with the total prosthesis?
On the total prosthesis, the surgeon is obliged to sacrifice the anterior cruciate ligament, that is to say, it is necessary to cut it to set up the total prosthesis.
“With the partial prosthesis, the cruciate ligament is preserved. Recovery is faster and returning to sport (including impact sports) is often easier and more enjoyable.”
What risks?
One of the main causes of failure is revision surgery for progression of osteoarthritis in another compartment of the knee. This cause accounts for regarding 3% of failures at age 25.
“In this case, one can either add another half-prosthesis or – and this is what is generally done – change the half-prosthesis for a total prosthesis.
Know +
The unicompartmental knee prosthesis, towards a new paradigm by Arnaud Clavé and Frédéric Dubrana. Collection “Medical specialties”. Price: 67 euro.
Example of unicompartmental knee prosthesis.Photo DR.
